The term "pen" in the context of the invention means any writing instrument, such as a fountain pen, ballpoint pen, mechanical pencil, felt-tip pen, or similar article including a tubular body and a rigid fastener clip that extends longitudinally of the body and is pivotably movable with respect to the body. The body in the present context may be the pen itself or a detachable cap.
Similar articles may be any articles that include a clip that in particular enables them to be attached, for instance to the pocket of an article of clothing.
Pen clips of known types, whether retractable or pivoting, are rigidly fastened to the body. If they are of the pivoting type, the clip works by its own elasticity, which has various disadvantages. In particular, it is difficult to make this clip adapt to different thicknesses of pockets in clothing.
On the other hand, known clips of both the retractable and the pivoting type have the disadvantage of including a complex, fragile mechanism both for fastening the clip to the body and for the elastic return of the clip toward the body.
Thus the known pivoting clips are generally articulated in the area of their upper portion on the body or on a piece connected to it, and for their elastic return toward the body they include a leaf spring that extends along the clip and is fastened in its lower portion to the vicinity of the free end of the clip, and in its upper portion to the body or to some piece connected to it.
In deluxe pens, for the sake of prestige and for esthetic reasons, the fastening and return mechanism, and in particular the leaf spring, must be especially reliable and must be invisible from the outside, so that as a result, the spring is typically accommodated inside the clip. This means that the clip has to be at least partly hollow, which lessens its rigidity and makes it fragile. Moreover, the clip is generally capable of relatively major lateral bottoming in the area of its free end, causing repeated strains on the clip, which results in damage to its fastening and return mechanism.